Grinding apparatus



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MAQ/ham H. F. HOLBECK GRINDING APPARATUS Filed April 4, 1935 Feb. 19, 1935.

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Feb. 19, 1935.

H. F. HoLBEcK GRINDING' APPARATUS AFiled Apr11'4, 1933 2 Sheets-Sheet 2 I l 1., :vu

@Mawr-j Array/Mrs' Patented Feb. 19, 1935 UNITED `STATES PATENT OFFICE. j

10 Claims.

This invention relates to apparatus for grinding coal and various other materials, and, as one of its objects aims to provide improved appara'- tus of this kind.

Another object of this invention is to provide improved apparatus, of the type referred to. having relatively rotatable cooperating annular grinding surfaces between which material is fed from the outer periphery, and having means for causing an air flow inwardly between the grinding surfaces. for removing fine material in opposition to centrifugal force.

Another object of this invention is to provide improved apparatus, wherein a grinding disc having one or more openings therethrough is arranged to rotate in y anv annularly extending grinding chamber, and wherein an air flow is created through the opening of the disc for removing ne material from the chamber.

A further object of my invention is to provide improved grinding apparatus, wherein a disc arranged to rotate in a chamber is provided with grinding means for cooperation with stationary grinding means, and wherein air iscaused to ilow inwardly through the chamber on both sides of the disc for removing material from the chamber in opposition to" centrifugal force.

Other objects and advantagesof the invention wil be apparent from the following description, when 'taken in conjunction with the accompanyin'g sheets of drawings, wherein y Fig. l is a longitudinal sectional elevation taken through a pulverizing machine constructed according to my invention.

Fig. 2 is a transverse sectional view thereof,

taken as indicated by line 2-2 of Fig. 1.

Fig. 3 is a longitudinal sectional elevation of another grinding machine constructed according to my invention.

Fig. 4 is a transverse sectional view thereof taken substantially on line 4-4 of Fig. 3.

Fig. 5 is a partial transverse sectional view taken substantially on line 5-5 of Fig. 1.

In the accompanying drawings, to which detailed reference will now be made, I have illustrated my improved apparatus which may be used for grinding coal and various other mate rials. The drawings illustrate what I now regard to be preferred forms of my invention, but it will be understood,of course, that the invention may be embodied in various other apparatus and in machines other than those herein illustrated.

The grinding apparatus illustrated in the drawings is of the type embodying cooperating stationary and movable grinding means, and utilizing an air flow for removing the finely ground material from the cooperating grinding means. As will be explained more fully hereinafter, the machines of my invention, although of compact 5 land relatively simple construction, are capable of efliciently handling large capacities, and are so constructed that the air ow is in opposition to the centrifugal or other directional effect produced on the material by the grinding means, such that only the nely ground material is withdrawn by the air ow, and the larger particles are retained in thefgrinding chamber.

The grinding machine illustrated in Figs. 1 and 2 of the drawings, is shown as having a suitable housing 10, which is preferably generally cylindrical in shape, but which may be provided with a squared bottom portion 11 forming a supporting base. The housing may be provided with a laterally extending portion 12 to form a suitable mount for an electric motor 13, which may be employed as the power means for driving the machine. As shown in Fig. 1 of the drawings, the housing 10 is provided further with a discharge chamber 14 at one end thereof, and with a main chamber 15 intermediate the fan chamber and the removablecover 16.

The discharge chamberv 14 may be separated from the main chamber 15 by a partition wall 17 having a substantially central opening 18 therethrough providing communication between the main chamber and the discharge chamber. The wall 1'7 may, if desired, be formed integral with the housing 10, but is preferably constructed as a removable disc, as shown in Fig. 1, which may be retained in place in the housing by the annular flange 19.

'I'he main chamber 15 may be subdivided into a plurality of grinding sections or annularly extending grinding chambers 20, 21 and 22. Any suitable number of such chambers may be provided, depending upon the size and capacity of the machine, and in this instance, I have shown three such chambers. These annular grinding chambers are formed by spaced discs or partition walls 23, 24 and 25, which are arranged to extend transversely of the main chamber 15, in substantially parallel relation to each other, between the partition wall 17 and the removable cover 16. These stationary partition walls are provided substantially centrally thereof with openings 26, which openings are in substantial alignment with, and may correspond in size with the openings 18 of the partition wall 17;

A shaft 27, driven by the motor 13, is suitably journaled in the housing and extends through the discharge chamber 14 and through the openings 26 of the partition walls. Disc-like grinding rotors are provided in number to correspond with the number of grinding chambers, and in this instance I prove three gringing discs 28 29 and 30, which are mounted in spaced relation on the shaft 27 and rotate, respectively, in the annular chambers, 20, 21 and 22. Each of these grinding discs is constructed with an annular web portion 31 which extends into an annular chamber formed between a pair of spaced stationary discs or walls, and with a hub portion 32 which is mounted on and drivingly connected with the shaft 27. 'Ihe hub portion 32 is connected with the web portion by means of spokes or arms 34. The discs and the partition walls are preferably so formed that the openings of the discs register with, and are substantially the same diameter as the openings of the partitions.

The web portions 31 of the discs are provided on opposite sides thereof with grinding means of suitable form, in this instance the grinding means comprises a grid arrangement of laterally extending ribs 35. This grinding means of the web portion cooperates-with grinding means provided on the partitions which form the side walls of the annular chambers. The latter grinding means may be of any suitable form, but is preferably similar to that provided on the discs, and may be a grid arrangement of laterally extending ribs 36. 'I'he grinding discs may also be provided with radial extensions or impact members 37, which are spaced circumferentially around thev outer periphery so as to project into the annular chambers outwardly of the grinding means on the side walls of these chambers.

As shown in the drawings, the partition walls 23, 24 and 25 may be integrally connected with cylindrical ring members 39, 40 and 41, which form liners for the respective annular chambers 20, 21,and 22. 'I'hese ring members are constructed of such size that they can be snugly assembled into the main chamber 15 of the housing, and when thus assembled are retained in engagement with each other between the partition 17 and the cover 16. The walls 23, 24 and 25 are connected to the respective ring members 39, 40 and 41, preferably at one edge thereof, so that when these members are assembled in the housing, as shown in Fig. 1, the walls 23, 24 and 25 are supported and retained in spaced relation by the ring members, to form the annularly extending grinding chambers. The ring members themselves constitute liners which form the cylindrical outer walls of the grinding chambers. If desired,-

the inner cylindrical surfaces of these ring members may be provided with teeth or corrugations 42, as shown in Fig. 2 of the drawings, for cooperation with the impact members 37 in breaking up the material.

As stated above, the walls 23, 24 and 25 are supported by the ring members by being connected to these members preferably at one edge thereof. If desired, the walls may be connected to the respective ring members by an imperforate anvnular rib or web extending around and forming a part of each wall outwardly of the grinding means thereon. I prefer, however, to connect the walls with their respective ring members by means of a plurality of radial arms 43 which are spaced around the walls outwardly of the grinding means, as shown in Figs. 1 and 2. 'I'he spaces between the arms of each wall thus provide paschamber through these openings. 5

For supplying the material to be ground, suitable means may be provided, such as the hopper 44, which supplies the material to a chamber 45 extending around the assembled ring members 39, 40 and 41. Material supplied to the chamber 45 by the hopper 44, enters the grinding chambers 20, 21 and 22, through openings 46, provided in the ring members 39, 40 and 41. The openings 46 may be provided in any suitable number, and may extend for any desired distance around the ring members, but, as shown in Fig. 2 of the drawings, I prefer to provide these openings only beneath or adjacent to the inner end of the hopper, and only in suiilcient number to afford the necessary cross-sectional area for feeding material into the grinding chambers at the desired rate. If desired, the chamber 45 may be allowed to fill up with the material to be ground and during the operation of the machine this chamber functions, as a pocket for collecting tramp metal which happens to be present in the material being supplied to the hopper. Such tramp metal settles downwardly through the accumulation of material in the chamber 45, and collects in the pocket 47 which is formed in the squared portion 11 of the machine.

In the discharge chamber 14 of the housing I provide a fan 50 which is mounted on and driven by the shaft 27. 'I'his fan is preferably arranged to rotate around the opening 18 of the partition wall 17, and may be of any suitable construction adapted to function eilciently in creating a flow of air from the main chamber 15 into the chamber 14, which chamber may also be referred to as a fan chamber. The fan chamber itself is preferably of volute form, and is provided with a substantially tangentially extending discharge connection 51, through which the air and finely ground material are delivered by the fan.

During the operation of the machine illustrated in Figs. 1 and 2, the material fed into the annular grinding chambers through the openings 46, is rst subjected to impacts by the spaced projections or hammers 37 of the grinding discs, and by the cooperation of these hammers with the corrugations 42 of the ring 'members, the material is subjected to an initial breaking or grinding action. Air drawn into the grinding chambers through the openings 46 by the action of the fan 50, passes inwardly through these chambers on both sides of the grinding discs therein, and tends to carry the material inwardly between the cooperating grinding means of the discs and side walls of the chambers. During such inward movement the material is subjected 60 to a grinding action, which reduces the material to a ne state. The material which is rendered fine by this action is carried inwardly by the air ow, and then travels laterally through` the aligned openings of the discs and partition walls and through the opening of the partition wall 17 into the fan chamber, from whence it is discharged through the tangential delivery pipe 51. Centrifugal force acting on the material in the grinding chambers tends to throw the larger particles of the material outwardly toward the ring members 39, 40 and 41, and the air flow moving inwardly in opposition to the centrifugal force,

'removes only the finely ground material from 75 tion 58.

varound the periphery thereof.

these chambers, the larger particles being retained therein for further grinding action.

In Figs. 3 and 4 of the drawings, I have shown my invention embodied in another grinding machine having a housing 55 ywhich is provided with a main chamber 56, and with a discharge chamber 57 which is separated from the main chamber by the removable partition wall 58. The main chamber 56 is divided into a plurality of annular grinding sections or chambers 59, 60, 61 and 62 by annularly extending stationary discs or partition walls 63, 64 and 65, which are supported in the housing, in spaced relation to each other, between the partition wall 58 and the removable cover 66 of the housing. The stationary partition walls 63, 64 and 65 are provided with openings 67 substantially centrally thereof, which openings are in substantial alignment with a similar opening in the partition 58.

A shaft 68 is suitably supported in the housing 55 to extend through the chamber 57 and through the openings 67 of the partition walls. This shaft may be driven by any suitable power means, such as the electric motor 69. A fan 70, which is mounted on and driven by the shaft 68, rotates in the chamber 57 to create an air flow into this chamber through the opening 67 of the parti- A plurality of disc-like rotors 71, 72, 73 and 74 are mounted on the shaft 68 in spaced relation for operation in the respective grinding chambers formed between the spaced stationary walls. These discs are constructed with annular web portions which extend into the annular grinding chambers, and which are provided on opposite surfaces thereof with suitable grinding means, such vas a grid arrangement of laterally projecting ribs 75. 'I'he grinding means of the discs cooperate with grinding means provided on the side walls of the Vannular chambers. The latter grinding means is of any suitable form, which will cooperatelefliciently with the grinding means of the discs, and may also comprise a grid arrangement of laterally projecting ribs 76.

As shown in the drawings, some of the discs, such as the discs 72 and 74, may be provided with openings, whichare vin substantial alignment with the lopcvenings 67 of the partition walls, and through 'which an air flow may be created by the fan 70. The end disc 71 and, if desired, an intermediate disc, such as the disc 73, are made imperforate, so that the air and material cannot pass through these discs but must pass The disc 7l, as shown in Fig, 3 of the drawings, is the initial grinding disc and may be constructed with the grinding means 75 on one side only thereof, `that is, on the side of this disc which is adjacent the partition wall 63.

It can be explained best at this point in the description that the stationary walls 63 and 65 are supported in the housing by circumferentially spaced arms 'I7 which connectthese walls with the ring members 79 and 81. The arms 77 support the walls 63 and 65 with portions of the outer periphery of these walls spaced from the ring members to form arcuately extending openings or passages 82 which connect adjacent grinding chambers. These openings are located outwardly of the grinding means on these walls and may be of any appropriate shape and area. These openings in the wall 63 provide peripheral passages connecting the annular chambers 59 and 60, and the outer openings in the wall 65 provide peripheral passages which connect the chamber 61 with the chamber 62. The wall 64 could, if

-described in Figs. 3 and 4, it will be seen th desired, -be provided with similar openings outwardly of the pulverizing means 76, but is preferably supported in the housing by an imperforate continuous annular connection with the ring member 80. Aside from its central opening the wall 64 is, in other words, imperforate so that all of the air and material passing this wall must travel through the central opening.

Material to be ground may be fed into the main chamber 56 of the machine through the passage 83 of the removable cover 66. Material thus fed into the chamber passes around the periphery of the imperforate end disc .71, and some of this material passes inwardly between the cooperating grinding means of this disc and the stationary wall 63.

Some of the material which is supplied to the periphery of the imperforate disc 71, passes directly through the outer openings of the partition wall 63 into the peripheral portion of the yannular chamber 60. The material thus enterthe fan 70, and such inward movement is inv opposition to centrifugal force acting on the material. The centrifugal force tends to throw out the larger particles toward the ring member, so that only the fine material can pass inwardly and be carried toward the fan chamber 57 by the air flow.

All of the finely ground material leaving the annular chamber 60 must pass through the central opening of the stationary wall 64, as stated above, and such material then enters the chamber 61 by moving outwardly between the cooperating grinding means provided onthe disc 73 and the stationary wall 64. The material then passes around the periphery of the imperforate disc 73, and some of the material moves .inwardly through the outer openings of the wall 65 into the grinding chamber 62. The material thus supplied to the chamber 62 moves inwardly on both sides of the disc 75, and is subjected toa grinding action by the cooperating means of this disc and the side walls of the chamber 62. The finely ground material leaving the chamber 62, passes through the opening of the partition 58 and there rrcunites with the nely ground material delivered from the chamber 6l. The air and ground material thus entering the fan chamber through the opening of the partitionwall 58, are discharged from the volute chamber 57 by the fan 70 through the substantially tangentially extending delivery connection 84.

If desired, the grinding disc 71 may be provided around the outer periphery thereof with spaced impact members or hammers 85, and likewise, the discs 72, 73 and 74 may also be provided around their outer peripheries with spaced impact members 86. These impact members cooperate with the teeth or corrugations 87, provided on the inner surfaces of the grinding chambers, in breaking upfthe larger particles of vthe material.

From the arrangement of the apparatus, as

atd

the ow of material which is supplied to the periphery of the disc 71 is divided, so that some of the material passes immediately inwardly between this disc and the stationary wall 63, and the remainder of the material passes through the outer openings of the disc 63 into the chamber 60. Likewise, the ow of material passing around the outer periphery of the imperforate disc 73 is divided so that some of this material flows inwardly between the disc 73 and the stationary wall 65, and the other portion of this ow passes directly through the outer openings of the Wall 65 into the chamber 62.

The spacing of the end disc 71 away from the wall of the removable cover 66, may be such as to provide a chamber 88, as shown in Fig. 3, in which some of the material being fed through the opening '78 accumulates, and in which tramp metal will be collected and retained to prevent damage to the grinding means.

In the several forms of grinding machines which I have disclosed, it will be noted that the air ilow created through the machine travels through the grinding chamber and between the cooperating grinding means in a direction opposed to centrifugal force, such that only the finely ground material is removed by the air flow. The larger particles of material are withheld against removal by the air i'low by the centrifugal force acting thereon. It will be noted further that in the several forms of grinding machines which I have disclosed, the cooperating grinding portions of the relatively movable discs are of extensive area and subject the material to a continuous grinding action from the'time the-,material is fed between these cooperating portions at their outer periphery until the material emerges in finely ground form at the inner periphery of these cooperating portions.

From the foregoing description and accompanying drawings it will also be readily seen that I have provided'improved grinding apparatus which is of very compact construction yet which is capable of eiliciently handling a large volume of material. This efcient operation is attained in my improved apparatus, as explained above, by the use of a continuous grinding action and by permitting only the nely ground material to be withdrawn from the grinding chamber by the air flow, while the larger particles are retained therein for further grinding, by the action of centrifugal force.

While I have illustrated and described my improved pulverizing apparatus in a detailed manner, it should be understood, however, that I do not wish to be limited to the precise details of construction and arrangements of parts illustrated and described, but regard my invention as including such changes and modifications as do not involve a departure from the spirit of the invention and the scope of the appended claims.

Having thus described my invention what I claim is:

1. In` a machine of the character described the combination of a housing having a chamber therein provided with spaced side walls, one of said walls having an opening substantially centrally thereof, a disc rotatable in said chamber between said walls, said disc having an opening registering substantially with theopening of said one wall, means for causing and air flow inwardly through said chamber on both sides of said discv and through said openings, means for feeding material to said chamber substantially at the periphery thereof, and cooperating means on said disc and walls for crushing the material being carried inwardly between the disc and said walls by the air ow.

2. In a machine of the character described the combination of a housing having a plurality of pairs of spaced stationary walls defining annular chambers, grinding means on the adjacent surfaces of the walls of each pair, said stationary walls having openings therethrough inwardly of the grinding means, a rotatable shaft in said openings, discs mounted on said shaft with portions thereof extending between said pairs of walls, grinding means on such disc portions for cooperation with the grinding means of said Walls, said discs having openings therethrough inwardly of the grinding means thereon, means for feeding material into said chambers substantially peripherally thereof, and means for causing air to flow inwardly through the chambers on both sides of the discs therein and through the openings of the discs and walls.

3. In a machine of the character described the combination of a housing having a fan chamber and a grinding chamber, a partition separating said chambers and having an opening therethrough, a power shaft extending into said chambers through said opening, means dividing the grinding chamber into a plurality'of grinding' sections including spaced stationary grinding discs each having an opening therethrough in substantial axial alignment `with the opening of said partition, a plurality of movable grinding discs mounted on said shaft and rotatable in the respective grinding sections, said movable grinding discs also having openings therethrough in substantial axial alignment with the openings of said stationary grinding discs and said partition, means for feeding material into said grinding sections substantially at the periphery thereof, and a fan rotatable in the fan chamber around the opening of said partition for creating an air ilow inwardly through said grinding sections on both sides of the grinding discs therein.

4. In a machine of the character described the combination of a housing having an annular chamber with grinding means on adjacent surfaces of the walls thereof, a disc rotatable in said housing with a portion thereof extending into said annular chamber, such disc portion having grinding means on opposite sides thereof for cooperation with the grinding means of the adjacent wall surfaces, one of said walls having an opening therethrough outwardly of its grinding means for feeding material into said chamber substantially peripherally of the disc, said disc and one of said walls having openings therethrough inwardly of said grinding means, and means for causing air to flowinwardly through the chamber on both sides of the disc for the removal of ne material through the last mentioned openings.

5. In a machine of the character described the combination of a housing having spaced walls defining an annular grinding chamber, said walls having grinding means on their adjacent surfaces and one of the walls being provided with grinding means on its opposite surface, said walls having substantially aligned openings therethrough inwardly of said grinding means and said one wall having openings therethrough outwardly of the grinding means'thereon, a rotatable shaft extending through said aligned openings, spaced discs on said shaft including a disc having grinding means cooperating with the grinding means of the adjacent wall surfaces and a disc having grinding means for cooperation with the grinding means of said opposite surface, the rst mentioned disc having an opening therethrough inwardly of its grinding means and the second mentioned disc being imperforate', means for peripherally feeding material to the cooperating grinding means of said imperforate disc and said one Wall and into said chamber through theouter openings of said one wall, and means for causing an air flow inwardly past the cooperating grinding means of said walls and discs.

6. In a machine of the character described the combination of a housing having spaced walls delining an annular grinding chamber, said Walls having substantially aligned central openings therethrough, a rotatable drive shaft extending through said central openings, a disc in the grinding chamber on said shaft and having an opening substantially aligned with said central openings, an imperforate disc on said shaft, cooperating grinding means on opposite sides of the first mentioned disc and the adjacent sides of said spaced walls and cooperating grinding means on the opposite side of one of said walls and the adjacent side of said imperforate disc, means for causing an air iiow inwardly past said cooperating grinding means and through said aligned openings, and means for peripherally feeding material to said cooperating grinding means both axially and circumferentially of the housing.

'7. In a grinding machine the combination -of a housing having a wall provided with a substantially central discharge opening and a partition wall spaced from said wall and also having a substantially central opening therethrough, discs in the housing including rotary and stationary discs disposed between said walls and having central openings substantially aligned with said discharge opening and an imperforate rotary disc on each side of said partition Wall, cooperating grinding means on said discs and walls, means for peripherally feeding material to said grinding means, and means causing an air flow inwardly of the grinding means and through said openings.

8. In a grinding machine the combination of a housing having spaced walls with an annular grinding chamber therebetween, said walls being provided respectively with substantially centrally disposed inlet and outlet openings, a plurality of cooperating grinding discs in said chamber including a stationary disc having a central opening therethrough and rotary discs adjacent said inlet and outlet openings,` the disc adjacent said .outlet opening having a central opening therethrough and the disc adjacent the inlet opening being imperforate, a second imperforate grinding disc on the opposite side of the wall containing said inlet opening, means for peripherally feeding material to said grinding discs,.and means causing an air iiow inwardly of the grinding discs and through said openings.

b 9. In a machine of the character described the combination of a housing having an annular chamber therein provided with inlet means adjacent one end and a substantially central discharge opening adjacent its other end, a.v plurality of axially spaced stationary discs in said chamber each having a substantially central opening therethrough and grinding means thereon around the opening, alternate ones of said stationary discs also having an opening therethrough outwardly of the grinding means and the intermediate stationary disc being imperforate outwardly of its grinding means, rotary discs in said chamber on opposite sides of the stationary discs and having grinding means thereon for cooperation with the grinding means of the stationary discs, said rotary discs including an imperforate disc ,adjacent said inlet means and an imperforate disc on the discharge side 'of and spaced from said intermediate disc to provide a transfer passage, the others of said rotary discs having substantially central openings therethrough, and means'for causing an airflow through said central openings and said transfer passage and inwardly past the cooperating grinding means.

10. In a machine of the character described the combination of a housing having an annular chamber therein provided with inlet means adjacent one end and a substantially central discharge opening adjacent its other end, alternate stationary and rotary discs in said chamber having cooperating grinding means thereon, said stationary discs including discs having openings therethrough substantially centrally thereof and also outwardly of their grinding means and an intermediate disc having a substantially central opening but being imperforate outwardly of its grinding means, said rotary discs including discs air ow through said central opening and said transfer passage and inwardly past the cooperating grinding means.

HALvoR F. HOLBECK. 

